Light emitting element adjusting and fixing structure, optical scanner, and image forming apparatus

#This application is based on and claims the priority benefit of each of Japanese Patent Application Nos. 2011-006352, filed on Jan. 14, 2011 and 2011-013461, filed on Jan. 25, 2011 the disclosure of which is incorporated herein by reference in its entirety.

#1. Field of the Invention

#The present invention relates to an optical scanner to be used in a writing optical system of an image forming apparatus such as a digital copier or a laser printer, and particularly to a technique for positioning and fixing a light emitting element having a plurality of light beams.

#FIG. 1 is a schematic front view of an image forming apparatus to which one embodiment of the present invention can be applied.

#FIG. 2 is a schematic view for explaining an optical scanner to be used in the one embodiment of the present invention.

#FIG. 3 is a schematic view for explaining the adjustment of a light emitting element in the one embodiment of the present invention.

#FIG. 1 shows an image forming apparatus in which one embodiment of the present invention is employed. In this drawing, an image forming apparatus 500 includes an optical scanner 100, four photosensitive drums 30A, 30B, 30C, and 30D, an intermediate transfer belt 40, a paper feed tray 60, a paper feed roller 54, registration roller pairs 52 and 56, fixing means 50, a delivery roller pair 58, unillustrated control means, an apparatus main body 501, and the like. On an upper surface of the apparatus main body 501, a paper output tray 501a to which printed sheets are delivered is provided. The optical scanner 100 is disposed under the paper output tray 501a. Based on image information sent from an unillustrated image reader or an external device, the optical scanner 100 scans a laser beam for a black image component across the photosensitive drum 30A, scans a laser beam for a cyan image component across the photosensitive drum 30B, scans a laser beam for a magenta image component across the photosensitive drum 30C, and scans a laser beam for a yellow image component across the photosensitive drum 30D.

#The photosensitive drums 30A, 30B, 30C, and 30D are provided next to one another under the optical scanner 100. Each of the photosensitive drums 30A, 30B, 30C, and 30D is rotationally driven in the clockwise direction in FIG. 1 by unillustrated drive means. Around the photosensitive drum 30A, charging means 32A, developing means 33A, and cleaning means 31A are arranged. The charging means 32A charges the surface of the photosensitive drum 30A to a predetermined voltage. The developing means 33A has a cartridge filled with a toner for a black component, a developing roller, and the like. The cleaning means 31A has a cleaning blade contacting with the surface of the photosensitive drum 30A and cleans the surface of the photosensitive drum 30A. Around each of the other photosensitive drums 30B, 30C, and 30D, except for the color of a toner stored in developing means, similar structures are arranged. The developing means 33B has a toner for a cyan component stored therein, the developing means 33C has a toner for a magenta component stored therein, and the developing means 33D has a toner for a yellow component stored therein.

#The intermediate transfer belt 40 in the form of an endless belt is passed over driven rollers 40a and 40c and a drive roller 40b to be placed such that an upper surface of the intermediate transfer belt 40 is in contact with the photosensitive drums 30A, 30B, 30C, and 30D, and is driven for running in the direction indicated by arrows in FIG. 1 by being rotationally driven by the drive roller 40b. At a position facing the driven roller 40c across the intermediate transfer belt 40, a transfer charger 48 as transfer means for applying a voltage of polarity opposite to that of the charging means 32A, 32B, 32C, and 32D to the intermediate transfer belt 40 is placed close to the intermediate transfer belt 40 at a predetermined distance therefrom.